The present invention relates to a spring hinge for automobile sunvisors.
More particularly, it relates to a spring hinge for an automobile sunvisor having a hollow body member produced by blow molding of a plastic material.
It is well known that the sunvisors normally fitted as original equipment in automobiles have a hinge formed, basically, by a pivot pin forming part of a bracket member attached to the vehicle structure and normally attached to the vehicle roof and by a spring which is fixedly attached to the sunvisor. The spring receives and retains the pivot pin so that the sunvisor may be rotated around the pivot pin and firmly hold any position, as selected by the user, in which it is placed among the normal positions of use. Furthermore, the pivot pin and retaining spring are provided with means, generally formed by respective positioning flats, which more firmly set the rest position or positions of the sunvisor.
In sunvisors including a hollow body member of essentially prismatic shape produced by blow molding of a plastics material and a retaining spring formed as a spring hinge for performing spring and hinge functions, the spring is housed completely within the hollow body member. It is accessible from the outside by means of a through hole provided in the hollow body member and receiving the corresponding portion of the pivot pin of the bracket member.
As an example of known embodiments of sunvisors such as those described above, in which the retaining spring formed as a spring hinge is completely housed within the hollow body member, there may be cited Spanish patent P 9100391. The patent P 9100391 discloses a retaining spring of essentially rectangular form, which is symmetrical about its longitudinal plane, defining two superimposed respectively semicylindrical and prismatic portions, in which the semicylindrical, or upper, portion receives the pivot pin of the bracket member.
The retaining spring disclosed in Spanish patent P 9100391 is positionally fixed inside the hollow body member by way of a plurality of recesses formed in the walls of said body member and flanking it and by the resilience of the spring itself, the side walls of which press directly against the corresponding inner surfaces of the side walls of the hollow body member. The fact that the retaining spring bears directly on the inner surfaces of the hollow body member means that when the user moves the sunvisor from the rest position(s) to any other position of use, or when the sunvisor is moved precisely to the rest position(s), the action of the pivot pin on the retaining spring, by deforming it, causes in turn deformation of the hollow body member after an extended period of use, precisely in the immediate surroundings of the position occupied by the retaining spring. Such deformation of the sunvisor hollow body member may be sufficiently serious to be felt by the touch, which is a drawback and, at times, even gives an irregular finish to the sunvisor.